Centaurea diluta
North african knapweed
(c) Manuel Fuentes Romero, some rights reserved (CC BY-SA) · licence
Family: Asteraceae · Type: Herb · Not Native
Conservation status: Cal-IPC Yes
Centaurea diluta (North african knapweed) is a non-native California herb in the Asteraceae family, recognized by low coastal elevation and large radiant pink-purple heads.
North African knapweed is a naturalized annual found in western coastal California and southern coastal regions in disturbed places at elevations below 170 meters. Flowering from April to December, this plant produces pink-purple flowers in radiant heads with distinctive fringed phyllary appendages. Growing up to 1.3 meters tall with openly branched stems that are puberulent or nearly hairless and resin-dotted, it develops a distinctive branching structure. Its lower leaves are 10 to 15 centimeters long with coarsely lobed margins, featuring a generally largest distal lobe, while upper leaves become progressively smaller and less complex. The fruit is approximately 3.5 millimeters long with white pappus bristles about 4.5 millimeters in length.
Identification and appearance
Key characters: 11 sympatric species; low coastal elevation and large radiant pink-purple heads are diagnostic
Habitat and range
Habitat: Disturbed places
Elevation: < 170 m
Outside California: native to southwestern Europe
Bloom period
Centaurea diluta blooms Apr-Dec.
Conservation status
Cal-IPC Yes
How to tell it apart
vs Cirsium: Cirsium bracts taper to simple spines; Centaurea bract tips expanded with fringed/toothed edges; vs Carduus: Carduus bracts spine-tipped but not fringed; Centaurea bract appendages distinctly fringed or toothed; vs Jacobaea: Jacobaea has obvious yellow ray flowers; Centaurea lacks true rays (all tubular flowers); vs Silybum: Silybum has white-veined leaves and simple spine-tipped bracts; Centaurea bracts ornately fringed; vs Eriophorum: Eriophorum is a sedge with grass-like leaves and cottony heads; Centaurea is a branched herb
Frequently asked questions
Is Centaurea diluta native to California?
No. Centaurea diluta is not native to California (recorded as not native).
When does Centaurea diluta bloom?
Centaurea diluta blooms Apr-Dec.
What plant family does Centaurea diluta belong to?
Centaurea diluta is in the Asteraceae family, genus Centaurea.
Is Centaurea diluta invasive in California?
Centaurea diluta is listed by Cal-IPC with an invasiveness rating of Yes.
What habitat does Centaurea diluta grow in?
Centaurea diluta grows in Disturbed places.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.